The invention relates to aluminum studs for snowmobile belt tracks. The invention is particularly useful for grass drag snowmobile racing, and can also be used for ice and snow snowmobile racing and high speed recreational snowmobiling.
Snowmobiles are normally propelled by a resilient belt track driven by sprocket drive wheels. Conventional belt tracks have transverse lugs for traction. To improve traction, it is well known to mount studs in the belting of the belt track between the transverse lugs. Snowmobile studs are typically made of hardened carbon steel. Hardened carbon steel has been used because of its durability. Most studs for ice tracks have a conical, ice-penetrating shank made of hardened steel with an ice-penetrating point. These studs are commonly referred to as picks. Studs for grass drag racing, or soft ice and hard packed snow conditions, are commonly referred to as spades or chisels. Spades or chisels have a flat rear face that is useful for gripping dirt, snow or ice.
There are generally two types of studs: push-through type studs and T-nut type studs. With a push-through stud, a shank of a stud projects perpendicularly from a head of the stud, and the shank is pushed through the belt track from the inside of the belt track. A backer plate or washer are then tightened onto threads on the shank from the outside of the belt with a nut. T-nut studs do not have a head, but have a transverse flange from which a penetration shank projects from a first side and threads project from the other side. To mount T-nut studs, the threads of the stud are passed through a backer plate or washer and through the belt track from the outside of the belt track, and a T-nut is tightened onto the stud threads from the inside of the belt track.
Heretofore, virtually all studs have been made of hardened carbon steel to withstand impact against dirt, ice or snow. Some steel studs even have a hardened carbide insert with a conical ice penetrating tip. Steel studs are durable and improve traction, but steel studs, along with the backer plates and the nuts, add weight to the belt track.
As the weight of the belt track increases, acceleration of the snowmobile is limited and the maximum top speed of the snowmobile is slower. It is therefore desirable to provide lightweight snowmobile studs having sufficient strength and durability.
The invention provides lightweight snowmobile studs, preferably made of aluminum, that have sufficient strength and durability for snowmobile racing on ice, snow or dirt, and for recreational snowmobiling on snowmobile trails. Aluminum studs weigh about 66 percent less than conventional steel studs (e.g. an aluminum stud can weigh about 3 to 4 grams, whereas a comparable steel stud can weigh 10 to 12 grams).